Contract law governs agreements between parties. This paper contains the chapters on contract law from a general, forthcoming book, Foundations of Economic Analysis of Law (Harvard University Press, 2003). Chapter 13 presents an overview of the subject. Chapter 14 is concerned with contract formation, that is, with the process through which parties find contracting partners, with aspects of contract negotiation, and with the rules governing when an arrangement between parties becomes legally recognized as a contract. Chapter 15 considers at length an important type of contract: the contract to produce something. Chapter 16 is concerned with two other types of contract: the contract for transfer of possession of something that already exists (such as land or a painting), and donative contracts.